A femtocell is an indoor cell in a home or office managed by a miniaturized base station that is connected through a broadband link to the core of a mobile communication network. The word ‘femtocell’ is a compound word formed from the word ‘femto’ meaning 10-15 and the word ‘cell’ meaning a coverage area for mobile communication, and refers to a cell having a radius of about 10 m. Femtocell base stations may contribute to extension of indoor cell coverage, enhancement of radio signal quality, and effective delivery of wired and wireless convergence services. Femtocell base stations enable subscribers to receive high-quality data services, and are expected to play a major role in both existing third generation mobile communication systems and next generation mobile communication systems such as 3GPP (The 3rd Generation Partnership Project) LTE (Long Term Evolution). A femtocell has much narrower coverage than a macro cell, and is normally deployed directly by the subscriber at a desired location.
In an environment of macro cells, a user equipment is readily able to identify a particular cell while approaching the cell. However, in an environment where 5000 to 7000 femtocells may be deployed in a unit area of 1 km2, a user equipment may have difficulty in identifying whether a neighbor cell is a macro cell or femtocell. Further, as discussed recently, a femtocell may operate in a closed access mode where the femtocell serves only a registered user, in an open access mode where the femtocell serves both a registered user and a non-registered user, or in a hybrid access mode where the closed access mode and open access mode are possible.
Accordingly, it is necessary for a user equipment to identify whether a neighbor cell is a macro cell or a femtocell, and, if the neighbor cell is a femtocell, to identify the access mode of the femtocell.